Not applicable.
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Not applicable.
1. Field of the Invention
The present invention relates to the field of digital cellular wireless telecommunications. In particular, the present invention is concerned with a cell for CDMA, wireless telecommunications in which capacity is increased by reconfiguring sector operations.
2. Description of the Prior Art
In the field of CDMA cellular/PCS telecommunications, a typical cell includes a base station unit controlling wireless communications using three sector antennas, each covering 120xc2x0. The base station unit uses a predefined set of sixty-four CDMA Walsh codes for each sector, with one of the codes used for a pilot channel, another for synchronization, one commonly used for paging, and the remainder available for ordinary traffic calls.
In actual usage, however, all of the remaining channels cannot be used for traffic because of noise accumulated in the band due to a variety of reasons such as interference from adjacent cells and unused multi-path signals. With the distinct advantages of PCS/cellular communications, demand for service is substantial and in some cases, may exceed cell capacity. In the prior art, one of the solutions has been to add more base stations at the same cells to provide increased capacity. This is an expensive solution because it requires additional base stations and equipment.
The present invention solves the prior art problems discussed above and provides a distinct advance in the state of the art. In particular, the system hereof provides an economical and time-effective way in which to increase the capacity of a cell in a cellular/PCS telecommunications network.
The preferred cell includes a cell site configured into a plurality of sectors having a plurality of antennas coupled with a base station unit for controlling transmission and reception over the antennas using selected ones of a defined set of CDMA codes for each of the sectors. A selected sector includes a plurality of antennas oriented to configure the selected sector into a corresponding plurality of subsectors, and the base station unit controls traffic using a different subset of the defined set of CDMA codes for each subsector.
In the preferred cell, the cell site includes three sectors with each having 64 Walsh codes that are split to service two subsectors. This configures the three-sector cell into a six-sector cell, thereby increasing the capacity of the cell.